Guidewire apparatus for temporary distal embolic protection

ABSTRACT

A guidewire apparatus for use during percutaneous catheter interventions such as angioplasty or stent deployment. A protection element comprising a filter or an occluder is mounted near the distal end of a steerable guidewire, which guides a therapeutic catheter. The guidewire apparatus comprises a hollow shaft movably disposed about a core wire. The shaft and core wire control relative displacement of the ends of the protection element, causing transformation of the protection element between a deployed configuration and a collapsed configuration. The protection element is freely rotatable about the guidewire apparatus. A tracking member disposed adjacent the distal end of the guidewire apparatus can be used to guide the device along another guidewire. Thrust bearings may be employed to facilitate unlimited rotation of the steerable guidewire within the protection element, especially while the protection element is retained in the collapsed configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 10/099,399 to Douk et al. filed Mar. 15, 2002 nowpending, which is a continuation-in-part of U.S. patent application Ser.No. 09/918,441 to Douk et al. filed Jul. 27, 2001, now pending, which isa continuation-in-part of U.S. patent application Ser. No. 09/824,832 toDouk et al. filed Apr. 3, 2001 now pending, entitled “TemporaryIntraluminal Filter Guidewire and Methods of Use.”

FIELD OF THE INVENTION

The present invention relates generally to intraluminal devices forcapturing particulate in the vessels of a patient. More particularly,the invention relates to a filter or an occluder for capturing emboli ina blood vessel during an interventional vascular procedure, thenremoving the captured emboli from the patient after completion of theprocedure. Furthermore, the invention concerns a filter or an occludermounted on a guidewire that can also be used to direct an interventionalcatheter to a treatment site within a patient.

BACKGROUND OF THE INVENTION

A variety of treatments exists for dilating or removing atheroscleroticplaque in blood vessels. The use of an angioplasty balloon catheter iscommon in the art as a minimally invasive treatment to enlarge astenotic or diseased blood vessel. When applied to the vessels of theheart, this treatment is known as percutaneous transluminal coronaryangioplasty, or PTCA. To provide radial support to the treated vessel inorder to prolong the positive effects of PTCA, a stent may be implantedin conjunction with the procedure.

Thrombectomy is a minimally invasive technique for removal of an entirethrombus or a sufficient portion of the thrombus to enlarge the stenoticor diseased blood vessel and may be accomplished instead of a PTCAprocedure. Atherectomy is another well-known minimally invasiveprocedure that mechanically cuts or abrades a stenosis within thediseased portion of the vessel. Alternatively, ablation therapies uselaser or RF signals to superheat or vaporize a thrombus within thevessel. Emboli loosened during such procedures may be removed from thepatient through the catheter.

During each of these procedures, there is a risk that emboli dislodgedby the procedure will migrate through the circulatory system and causeischaemic events, such as infarction or stroke. Thus, practitioners haveapproached prevention of escaped emboli through use of occlusiondevices, filters, lysing, and aspiration techniques. For example, it isknown to remove the embolic material by suction through an aspirationlumen in the treatment catheter or by capturing emboli in a filter orocclusion device positioned distal of the treatment area.

SUMMARY OF THE INVENTION

The guidewire apparatus of the invention includes a protection elementcomprising a filter or an occluder mounted near the distal end of asteerable guidewire, which guides a therapeutic catheter. The guidewireapparatus comprises a hollow shaft movably disposed about a core wireand, optionally, a slippery liner interfitted there between. The shaftand core wire control relative displacement of the ends of theprotection element, causing transformation of the protection elementbetween a deployed configuration and a collapsed configuration. Theprotection element is freely rotatable about the guidewire apparatus. Atracking member disposed adjacent the distal end of the guidewireapparatus can be used to guide the device along another guidewire.Thrust bearings may be employed to facilitate unlimited rotation of thesteerable guidewire within the protection element, especially while theprotection element is retained in the collapsed configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects and advantages of the present invention will becomebetter understood with reference to the following description, appendedclaims, and accompanying drawings where:

FIG. 1 is an illustration of a filter system in accordance with theinvention deployed within a blood vessel.

FIG. 2 is an illustration of a filter system in accordance with theinvention deployed within a portion of the coronary arterial anatomy;

FIG. 3 is an illustration of a prior art expandable mesh device, shownwith the mesh in a collapsed configuration;

FIG. 4 is an illustration of a prior art expandable mesh device, shownwith the mesh in a deployed configuration;

FIG. 5 is a longitudinal sectional view of a first guidewire embodimentin accordance with the invention;

FIG. 6 is a longitudinal sectional view of a second guidewire embodimentin accordance with the invention;

FIG. 7 is a cross-sectional view of the second guidewire embodimenttaken along the lines 7—7 of FIG. 6;

FIG. 8 is a modified form of the cross-sectional view shown in FIG. 7;

FIG. 9 is another modified form of the cross-sectional view shown inFIG. 7;

FIG. 10 is an enlarged supplementary view of a portion of FIG. 8, whichhas been modified to illustrate alternative embodiments of theinvention;

FIG. 11 is a longitudinal sectional view of a segment of a hollow shaftand liner in accordance with the invention;

FIG. 12 is a partially sectioned longitudinal view of a third guidewireembodiment in accordance with the invention; and

FIG. 13 is a partially sectioned longitudinal view of a fourth guidewireembodiment in accordance with the invention;

FIG. 14 is a partially sectioned longitudinal view of a fifth guidewireembodiment in accordance with the invention;

FIG. 15A is an enlarged view of a stop element assembly shown in FIG.14;

FIG. 15B is an enlarged view of a modified form of the stop elementassembly shown in FIG. 14; and

FIG. 16 is a partially sectioned longitudinal view of a sixth guidewireembodiment in accordance with the invention

The drawings are not to scale.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a guidewire apparatus for use in minimallyinvasive procedures. While the following description of the inventionrelates to vascular interventions, it is to be understood that theinvention is applicable to other procedures where the practitionerdesires to capture embolic material that may be dislodged during theprocedure. Intravascular procedures such as PTCA or stent deployment areoften preferable to more invasive surgical techniques in the treatmentof vascular narrowings, called stenoses or lesions. With reference toFIGS. 1 and 2, deployment of balloon expandable stent 5 is accomplishedby threading catheter 10 through the vascular system of the patientuntil stent 5 is located within a stenosis at predetermined treatmentsite 15. Once positioned, balloon 11 of catheter 10 is inflated toexpand stent 5 against the vascular wall to maintain the opening. Stentdeployment can be performed following treatments such as angioplasty, orduring initial balloon dilation of the treatment site, which is referredto as primary stenting.

Catheter 10 is typically guided to treatment site 15 by a guidewire. Incases where the target stenosis is located in tortuous vessels that areremote from the vascular access point, such as coronary arteries 17shown in FIG. 2, a steerable guidewire is commonly used. According tothe present invention, a guidewire apparatus generally guides catheter10 to treatment site 15 and includes a distally disposed protectionelement to collect embolic debris that may be generated during theprocedure. Various embodiments of the invention will be described aseither filter guidewires or occluder guidewires. However, it is to beunderstood that filters and occluders are interchangeable types ofprotection elements among the inventive structures disclosed. Theinvention is directed to embolic protection elements wherein relativemovement of the ends of the protection element either causes oraccompanies transformation of the element between a collapsedconfiguration and an expanded, or deployed configuration. Suchtransformation may be impelled by external mechanical means or byself-shaping memory (either self-expanding or self-collapsing) withinthe protection element itself. The protection element may beself-expanding, meaning that it has a mechanical memory to return to theexpanded, or deployed configuration. Such mechanical memory can beimparted to the metal comprising the element by thermal treatment toachieve a spring temper in stainless steel, for example, or to set ashape memory in a susceptible metal alloy such as a nickel-titanium(nitinol) alloy.

Filter guidewires in accordance with the invention include distallydisposed filter 25, which may comprise a tube formed by braidedfilaments that define pores and have at least one proximally-facinginlet opening 66 that is substantially larger than the pores.Alternative types of filters may be used in filter 25, such as filterassemblies that include a porous mesh mounted to expandable struts.Optionally, adding radiopaque markers to filter ends 27, 29, as shown inFIG. 12, can aid in fluoroscopic observation of filter 25 duringmanipulation thereof. Alternatively, to enhance visualization of braidedfilter 25 under fluoroscopy, at least one of the filaments may be a wirehaving enhanced radiopacity compared to conventional non-radiopaquewires suitable for braiding filter 25. At least the majority of braidingwires forming filter 25 should be capable of being heat set into thedesired filter shape, and such wires should also have sufficient elasticproperties to provide the desired self-expanding or self-collapsingfeatures. Stainless steel and nitinol monofilaments are suitable forbraiding filter 25. A braiding wire having enhanced radiopacity may bemade of, or coated with, a radiopaque metal such as gold, platinum,tungsten, alloys thereof, or other biocompatible metals that, comparedwith stainless steel or nitinol, have a relatively high X-rayattenuation coefficient. One or more filaments having enhancedradiopacity may be inter-woven with non-radiopaque wires, or all wirescomprising filter 25 may have the same enhanced radiopacity.

In accordance with the invention, maintaining filter 25 in a collapsedconfiguration during introduction and withdrawal of filter guidewire 20does not require a control sheath that slidingly envelops filter 25.Thus, this type of device is sometimes termed as “sheathless.” Knowntypes of sheathless vascular filter devices are operated by a push-pullmechanism that is also typical of other expandable braid devices, asshown in FIGS. 3 and 4. Prior art expandable mesh device 30 includescore wire 32 and hollow shaft 34 movably disposed there about. Tubularmesh, or braid 36 surrounds core wire 32 and has a braid distal endfixed to core wire distal end 40 and a braid proximal end fixed to shaftdistal end 41. To expand braid 36, core wire 32 is pulled and shaft 34is pushed, as shown by arrows 37 and 39 respectively in FIG. 4. Therelative displacement of core wire 32 and shaft 34 moves the ends ofbraid 36 towards each other, forcing the middle region of braid 36 toexpand. To collapse braid 36, core wire 32 is pushed and shaft 34 ispulled, as shown by arrows 33 and 35 respectively in FIG. 3. Thisreverse manipulation draws the ends of braid 36 apart, pulling themiddle region of braid 36 radially inward toward core wire 32.

Referring now to FIG. 5, in a first embodiment of the invention, filterguidewire 20 includes core wire 42 and flexible tubular tip member 43,such as a coil spring, fixed around the distal end of core wire 42. Thinwires made from stainless steel and/or one of various alloys of platinumare commonly used to make coil springs for such use in guidewires. Corewire 42 can be made from shape memory metal such as nitinol, or astainless steel wire, and is typically tapered at its distal end. Fortreating small caliber vessels such as coronary arteries, core wire 42may measure about 0.15 mm (0.006 inch) in diameter.

In filter guidewire 20, hollow shaft 44 is movably disposed around corewire 42, and includes relatively stiff proximal portion 46 andrelatively flexible distal portion 48. Proximal portion 46 may be madefrom thin walled stainless steel tubing, usually referred to as hypotubing, although other metals, such as nitinol, can be used. Variousmetals or polymers can be used to make relatively flexible distalportion 48. One appropriate material for this element is thermosetpolyimide (PI) tubing, available from sources such as HV Technologies,Inc., Trenton, Ga., U.S.A. The length of distal portion 48 may beselected as appropriate for the intended use of the filter guidewire. Inone example, portion 48 may be designed and intended to be flexibleenough to negotiate tortuous coronary arteries, in which case the lengthof portion 48 may be 15-35 cm (5.9-13.8 inches), or at leastapproximately 25 cm (9.8 inches). In comparison to treatment of coronaryvessels, adaptations of the invention for treatment of renal arteriesmay require a relatively shorter flexible portion 48, and neurovascularversions intended for approaching vessels in the head and neck mayrequire a relatively longer flexible portion 48.

When filter guidewire 20 is designed for use in small vessels, shaft 44may have an outer diameter of about 0.36 mm (0.014 inch). The generaluniformity of the outer diameter may be maintained by connectingproximal portion 46 and distal portion 48 with lap joint 49. Lap joint49, and all other adhesive joints in the invention, may use any suitablebiocompatible adhesive such as ultraviolet (UV) light curable adhesives,thermally curable adhesives or so-called “instant” cyanoacrylateadhesives from Dymax Corporation, Torrington, Conn., U.S.A or LoctiteCorporation, Rocky Hill, Conn., U.S.A. Lap joint 49 can be formed by anyconventional method such as reducing the wall thickness of proximalportion 46 in the region of joint 49, or by forming a step-down indiameter at this location with negligible change in wall thickness, asby swaging.

Expandable tubular filter 25 is positioned generally concentrically withcore wire 42, and is sized such that when it is fully deployed, as shownin FIGS. 1 and 2, the outer perimeter of filter 25 will contact theinner surface of the vessel wall. The surface contact is maintainedaround the entire vessel lumen to prevent any emboli from slipping pastfilter 25. Adhesive may be used to secure filter distal end 27 to tipmember 43, and to secure filter proximal end 29 near the distal end ofshaft 44. As shown in FIGS. 12 and 13, radiopaque marker bands, such asplatinum rings, can be incorporated into the adhesive joints securingfilter ends 27, 29 respectively to tip member 43 and shaft 44. Filter 25is deployed by advancing, or pushing shaft 44 relative to core wire 42such that filter distal and proximal ends 27, 29 are drawn toward eachother, forcing the middle, or central section of filter 25 to expandradially. Filter 25 is collapsed by withdrawing, or pulling shaft 44relative to core wire 42 such that filter distal and proximal ends 27,29 are drawn apart from each other, forcing the middle, or centralsection of filter 25 to contract radially.

Transition sleeve 45 is fixed about core wire 42 and is slidably locatedwithin the distal end of flexible distal portion 48 of hollow shaft 44.Transition sleeve 45 may be made of polyimide tubing similar to thatused in distal portion 48 and extends distally there from. By partiallyfilling the annular space between core wire 42 and shaft 44, and bycontributing additional stiffness over its length, sleeve 45 supportscore wire 42 and provides a gradual transition in overall stiffness offilter guidewire 20 adjacent the distal end of shaft 44. Transitionsleeve 45 is fixed to core wire 42 with a suitable adhesive, such thatrelative displacement between shaft 44 and core wire 42 causescorresponding relative displacement between shaft 44 and sleeve 45. Thelength and mounting position of sleeve 45 are selected such that sleeve45 spans the distal end of shaft 44 regardless of the configuration offilter 25 and the corresponding position of shaft 44 relative to corewire 42. When constructed as described above, filter guidewire 20provides the functions of a temporary filter combined with theperformance of a steerable guidewire.

FIG. 6 depicts a second embodiment of the invention in which filterguidewire 120 incorporates a number of elements similar to the elementsthat make up filter guidewire 20. Such similar elements will beidentified with the same reference numerals throughout the descriptionof the invention. Filter guidewire 120 includes core wire 142 andflexible tubular tip member 43 fixed around the distal end of core wire142, similar to the arrangement of guidewire 20, above. Hollow shaft 144is movably disposed around core wire 142 and is comparable, throughoutits length, to relatively stiff proximal portion 46 of filter guidewire20. Filter 25 is positioned generally concentrically with core wire 142.Filter distal end 27 is fixedly coupled to tip member 43, and filterproximal end 29 is fixedly coupled near the distal end of shaft 144.

Optionally, a portion of core wire 142 within the proximal end of shaft144 has one or more bends 160 formed therein. The amplitude, or maximaltransverse dimension of bends 160 is selected such that the bent portionof core wire 142 fits, with interference, within shaft 144. Theinterference fit provides sufficient friction to hold core wire 142 andshaft 144 in desired axial positions relative to each other, therebycontrolling the shape of filter 25, as described above with respect tofilter guidewire 20.

In filter guidewire 120, liner 145 is interfitted as a low-frictionaxial bearing in the annular space between core wire 142 and shaft 144.With respect to the three coaxially arranged elements, the selecteddimensions and the stack-up of dimensional tolerances will determine howliner 145 functions during the push-pull operation of core wire 142within shaft 144.

For example, FIG. 7 depicts a cross-section of filter guidewire 120 inwhich there is radial clearance between liner inner surface 150 and corewire 142, and there is also radial clearance between liner outer surface151 and the inner wall of shaft 144. In this arrangement, liner 145 isradially free-floating in the annular space between core wire 142 andshaft 144. The length of liner 145 is selected such that it also“floats” axially along core wire 142. The axial movement of liner 145along core wire 142 is limited proximally by a stop formed at theengagement of bends 160 with the inner wall of shaft 144. Tip member 43limits the axial distal movement of liner 145 along core wire 142. Theradial and axial flotation of liner 145 in filter guidewire 120 providesan axial bearing wherein the components with the lesser relativecoefficient of friction can slide against each other. For example, ifthe coefficient of friction between liner inner surface 150 and corewire 142 is less than the coefficient of friction between liner outersurface 151 and the inner wall of shaft 144, then liner 145 will remainlongitudinally fixed within shaft 144, and push-pull action will causecore wire 142 to slide within liner 145. Conversely, if the coefficientof friction between liner inner surface 150 and core wire 142 is greaterthan the coefficient of friction between liner outer surface 151 and theinner wall of shaft 144, then liner 145 will remain longitudinally fixedabout core wire 142, and push-pull action will cause shaft 144 to slideover liner 145. The relative coefficients of friction for the movablecomponents of the guidewire assembly may be designed-in by selection ofmaterials and/or coatings, as will be described below. Alternatively,the degree of sliding friction may result from unplanned events, such asthe formation of thrombus on one or more component surfaces or embolicdebris entering the annular space(s) there between.

FIG. 8 depicts a modified form of the cross-sectional view shown in FIG.7 in which liner 145′ is fitted against the inner wall of shaft 144,leaving radial clearance only between liner inner surface 150′ and corewire 142. FIG. 9 depicts another modified form of the cross-sectionalview shown in FIG. 7 in which liner 145″ is fitted against core wire142, leaving radial clearance only between liner outer surface 151′ andthe inner wall of shaft 144.

When filter guidewire 120 is designed for use in small vessels, shaft144 may have an outer diameter of about 0.36 mm (0.014 inch), and corewire 142 may measure about 0.15 mm (0.006 inch) in diameter. Shaft 144,which can be made from hypo tubing, may have an inside diameter of about0.23 mm (0.009 inch). For liner 145 to “float” in an annular spacebetween core wire 142 and shaft 144 with such dimensions, liner outersurface 151 may measure about 0.22 mm (0.0088 inch) in diameter andliner inner surface 150 may measure about 0.18 mm (0.0069 inch) indiameter. Liner 145′ does not require clearance around its outsidediameter, because it is fitted against the inner wall of shaft 144. Ascompared to liner 145, liner 145′ may have a greater wall thickness, andliner inner surface 150′ may have a similar inner diameter of about 0.18mm (0.0069 inch). Liner 145″ does not require inside clearance becauseit is fitted against core wire 142. As compared to liner 145, liner 145″may also have greater wall thickness, and liner outer surface 151′ mayhave a similar outer diameter of about 0.22 mm (0.0088 inch).

Liners 145, 145′ and 145″ may be formed of polymers selected to providelow coefficients of friction on their sliding surfaces. Typical of suchpolymers are polytetrafluoroethylene (PTFE), fluorinatedethylene-propylene (FEP), high-density polyethylene (HDPE), and variouspolyamides (nylons). Alternatively, liners 145, 145′ and 145″ may beformed of a material selected for physical properties other than a lowcoefficient of friction, i.e. stiffness or ability to be formed withtight dimensional tolerances. For such materials, a slippery coating,such as silicone, may be applied to the sliding surface(s) in order toachieve the desired low-friction axial bearing properties.

Thermoset polyimide (PI) is an example of a liner material that may beselected for properties other than its coefficient of friction. PItubing is noted for its ability to be formed with tight dimensionaltolerances because it is typically formed by building up several layersof cured PI coating around a solid glass core, which is removed bychemical etching. One method of creating a slippery surface on PI tubingis to add a fluoropolymer filler, such as PTFE or FEP, to the PI coatingto form one or more low-friction layers at the desired surface(s). Suchpolyimide/fluoropolymer composite tubing is available from MicroLumen,Inc., Tampa, Fla., U.S.A. FIG. 10 illustrates a modified form of theinvention wherein the inner surface of liner 145′ comprises lubriciouscoating 150′. Also shown in FIG. 10 is slippery coating 155, which maybe applied to core wire 142 in conjunction with, or instead of, aslippery inner surface of liners 145 or 145′. Coating 155 may comprise athin film of, for example, silicone or a fluoropolymer.

Another example of a liner material that may be selected for propertiesother than its coefficient of friction is a block copolymerthermoplastic such as polyethylene block amide (PEBA). Although aslippery coating may be applied to this material, alternatively,plasma-aided surface polymerization may be used to reduce itscoefficient of friction. Plasma-aided surface functionalization toachieve high lubricity is described in U.S. Pat. No. 4,693,799(Yanagihara et al.), and plasma surface modification is available fromAST Products, Inc., Billerica, Mass., U.S.A. Plasma treated PEBA may besubstituted for PTFE in liners to make use of improved physicalproperties, including the ability to be plastically extruded.

FIG. 11 depicts a variant of liner 145′ disposed within hollow shaft144. In this example, liner 145′ comprises a coiled filament, which maybe plastic, metal, or coated or surface-treated forms of eithermaterial. The coiled variant may be applied to any of liners 145, 145′or 145″, and it provides reduced contact area and concomitantly lowerfriction as compared to solid tubular liners. Hollow tube 144 and corewire 142 will only touch coiled liner 145′ on helical curvilinearportions of the outer and inner surfaces, respectively. If coiled liner145′ is made with an outer diameter larger than the inner diameter ofhollow tube 144, then liner 145′ will generally hold itself in assembledposition against the inner diameter of hollow tube 144. Similarly, ifliner 145″ is made as a coil with an inner diameter smaller than thediameter of core wire 142, then liner 145″ will generally hold itself inassembled position around core wire 142.

FIG. 12 depicts a third embodiment of the invention in which filterguidewire 220 incorporates several elements that are similar to thecomponents of filter guidewires 20 and 120. Core wire 242 is disposedwithin liner 145, which is disposed within hollow shaft 144. Core wire242 is comprised of proximal section 256 and separate distal section258, which extends distally from shaft 144. Sliding clearance(s) may beformed between different elongate movable components, as described aboveand as shown in FIGS. 7, 8 and 9. If liner 145 is fitted against corewire 242, as shown in FIG. 9, then liner 145 will comprise separateproximal and distal sections (not shown) corresponding to core wireproximal section 256 and core wire distal section 258. Flexible tubulartip member 43 is fixed around the distal end of core wire distal section258. Transition sleeve 270 is slidably disposed about a distal portionof hollow shaft 144 and extends distally there from to a fixed couplinglocation on tip member 43. Filter 25 is self-expanding and is positionedgenerally concentrically with the distal portion of shaft 144. Filterdistal end 27 is fixedly coupled to transition sleeve 270, and filterproximal end 29 is fixedly coupled to shaft 144 adjacent the distalportion thereof.

Prior to negotiating vascular anatomy with filter guidewire 220, filter25 may be collapsed by advancing core wire proximal section 256 withinshaft 144 and liner 145 until the distal end of proximal section 256abuts the proximal end of distal section 258, forming continuous corewire 242. Continued advancement of core wire 242 through shaft 144 andliner 145 will displace tip member 43 distally away from shaft 144. Theaxial translation of tip member 43 will draw sleeve 270 distally along,but not off of, the distal portion of hollow shaft 144. The relativelongitudinal movement of sleeve 270 with respect to shaft 144 causesfilter distal end 27 to move away from filter proximal end 29,transforming filter 25 from its expanded configuration to its collapsedconfiguration. Optionally, filter guidewire 220 may include bends 160(not shown) in core wire proximal section 256 to provide frictionalengagement between core wire 242 and the proximal end of shaft 144. Asdescribed above regarding filter guidewire 120, the optional frictionmechanism thus created can hold core wire 242 in a selected axialposition within shaft 144, thereby retaining filter 25 in the collapsedconfiguration.

Withdrawing core wire proximal section 256 proximally through shaft 144and liner 145 allows filter 25 to transform itself towards the expandedconfiguration by drawing filter ends 27, 29 closer together. Theself-transformation of filter 25 towards the expanded configurationcauses simultaneous proximal movement of sleeve 270, tip member 43 andcore wire distal section 258 relative to shaft 144. The self-expansionof filter 25 stops when a) filter 25 reaches its pre-formed expandedconfiguration, or b) filter 25 encounters a radial constraint, such asapposition with a vessel wall in a patient, or c) filter 25 encountersan axial constraint, such as the proximal end of sleeve 270 contactingfilter proximal end 29, as depicted in FIG. 12. After self-expansion offilter 25 has stopped, any further withdrawal of core wire proximalsection 256 will cause it to separate from core wire distal section 258,thereby allowing core wire distal section 258, tip member 43, and sleeve270 to move freely with respect to the distal end of hollow shaft 144.In this configuration, core wire proximal section 256 will not interferewith self-expansion or self-adjustment of filter 25 in its appositionwith the vessel wall.

Transition sleeve 270 may be made of polyimide tubing and may be fixedto tip member 43 and to filter distal end 27 with a suitable adhesive.The length and mounting position of sleeve 270 are selected such thatsleeve 270 always surrounds the distal end of shaft 144, regardless ofthe configuration and length of filter 25. Sleeve 270 can support corewire 242 across the longitudinal gap between the distal end of shaft 144and the proximal end of tip member 43. By contributing additionalstiffness over its length, sleeve 270 also provides a transition inoverall stiffness of filter guidewire 220 adjacent the distal end ofshaft 144.

FIG. 13 depicts a fourth embodiment of the invention in which occluderguidewire 320 incorporates several elements that are similar to thecomponents of filter guidewires 20, 120, and 220. As distinguished fromfilter guidewire embodiments of the invention, occluder guidewires aretypically used to temporarily obstruct fluid flow through the vesselbeing treated. Any embolic debris trapped upstream of the occluderelement may be aspirated using a separate catheter, with or withoutirrigation of the area. Core wire 342 is disposed within liner 145,which is disposed within hollow shaft 144. Alternatively, liners 145′ or145″ may be substituted for liner 145 such that different slidingclearance(s) may be formed between different elongate movablecomponents, as described above and as shown in FIGS. 7, 8 and 9.Flexible tubular tip member 43 is fixed around the distal end of core342. Transition sleeve 270 is slidably disposed about a distal portionof hollow shaft 144 and extends distally there from to a slidingcoupling location on tip member 43. Proximal stop 381 protrudes radiallyoutward from the proximal end of tip member 43, and distal stop 382protrudes radially inward from the distal end of transition sleeve 270.Stops 381, 382 interact to prevent the distal end of transition sleeve270 from sliding proximally off of tip member 43. Proximal stop 381 maycomprise a portion of tip member 43, such as one or more enlarged turnsat the proximal end of a coil spring. Alternatively, proximal stop 381may be created with metal or plastic elements, such as solder orpolyimide bands. Distal stop 382 may comprise a portion of transitionsleeve 270, such as a rim or neck of reduced diameter formed at thedistal end thereof. Alternatively, distal stop 382 may be created withmetal or plastic elements, such as polyimide rings or bands.

Occluder 325 is self-expanding and is positioned generallyconcentrically with the distal portion of shaft 144. Similar to filter25, occluder 325 may comprise a tubular braid, which in this embodimentis coated with an elastic material to render it non-porous.Alternatively, occluder 325 may include self-expanding struts (notshown) that support a non-porous elastic membrane, as known to those ofordinary skill in the art. A non-porous coating or membrane may be madefrom a variety of elastic materials, such as silicone rubber or athermoplastic elastomer (TPE). Occluder distal end 327 is fixedlycoupled to transition sleeve 270, and occluder proximal end 329 isfixedly coupled to shaft 144 proximally adjacent the distal portionthereof.

In occluder guidewire 320, occluder 325 may be collapsed by advancingcore wire 342 through shaft 144 and liner 145, causing tip member 43 totranslate within transition sleeve 270 until proximal stop 381 engagesdistal stop 382, as shown in FIG. 13. Continued advancement of core wire342 through shaft 144 and liner 145 will displace tip member 43 distallyfrom shaft 144, drawing sleeve 270 along, but not off of, the distalportion of hollow shaft 144. The relative longitudinal movement ofsleeve 270 with respect to shaft 144 causes occluder distal end 327 tomove away from occluder proximal end 329, which transforms occluder 325from its expanded configuration to its collapsed configuration.Reversing the above manipulation, i.e. drawing core wire 342 proximallythrough shaft 144 and liner 145, permits occluder 325 to expand itself.Self-expansion of occluder 325 will stop when one of several conditionsis met, as described above with respect to self-expanding filter 25 offilter guidewire 220. Thereafter, continued withdrawal of core wire 342will draw tip member 43 proximally within transition sleeve 270,creating axial separation (not shown) between stops 381, 382, therebyallowing the distal end of transition sleeve 270, with distal stop 382,to slide freely along tip member 43. In this configuration, core wire342 and tip member 43 will not interfere with self-expansion orself-adjustment of occluder 325 in its apposition with the vessel wall.

FIG. 13 illustrates the portion of core wire 342 within hollow shaft 144having a first proximal segment 390, which also extends proximally fromhollow shaft 144. First proximal segment 390 is sized to fit slidinglywithin hollow shaft 144, but without sufficient radial clearance forliners 145, 145′ or 145″. First proximal segment 390 may comprise amajor length of core wire 342, such that relatively short core wiredistal segment 391 is dimensioned to receive liners 145, 145′ or 145″.For example, if occluder guidewire 320 is designed for use in coronaryarteries, then the overall length of core wire 342 may be about 175 cm,and the length of core wire distal segment 391 may be about 15 to 25 cm.Alternatively, first proximal segment 390 may have a relatively shortlength such that core wire distal segment 391 and surrounding liners145, 145′ or 145″ extend through a major length of hollow shaft 144.

The transition in diameter between core wire distal segment 391 andfirst proximal segment 390 may occur as step 398, which can limit theproximal slippage of free-floating liner 145 along core wire 342.Optionally, occluder guidewire 320 may exclude any liner while stillincorporating stepped diameter core wire 342 shown in FIG. 13. In suchan arrangement, the annular space that would otherwise be occupied by aliner can provide enlarged clearance and accompanying reduced frictionbetween core wire 342 and hollow shaft 144, especially when occluderguidewire 320 is curved through tortuous anatomy. Core wire 342 may alsooptionally include bends 160 (not shown) located distal to firstproximal segment 390.

In order to steer a distal protection guidewire in accordance with theinvention through tortuous vasculature, tip member 43 is typically bentor curved prior to insertion of the device, which should transmit to tipmember 43 substantially all of the rotation, or torque applied by theclinician at the proximal end of the device. It is most convenient forthe physician to steer the device by grasping and rotating shaft 144,and having such rotation imparted to tip member 43, either directly orthrough the core wire. In distal protection guidewires of the instantinvention, various design features reduce longitudinal friction betweenthe hollow shaft and the core wire. These same friction-reducingfeatures also reduce rotational friction between the hollow shaft andthe core wire, which would otherwise be useful in transmitting rotationto steer the device. In filter guidewires 20, 120 and 220, torque istransmissible from shaft 144 to tip member 43 through the braidedstructure of filter 25, however this action is generally effective onlywhen filter 25 is in the collapsed configuration. In occluder guidewire320, occluder distal end 327 is slidably connected to tip member 43through transition sleeve 270 such that torque cannot be transmittedfrom shaft 144 to tip member 43 through occluder 325.

It is therefore advantageous, as shown in occluder guidewire 320, toinclude a torque-transmitting element, such as torque member 384. Torquemember 384 can comprise metal or plastic filaments that form a hollowtube of counter wound spirals or a braid. To minimize bulk andstiffness, torque member 384 may include only a single filament in eachof the clockwise and counter clockwise winding directions. The proximalend of torque member 384 is bonded to the distal end of shaft 144 andextends distally there from to surround core wire 342 over a relativelyshort distance. The distal end of torque member 384 is bonded to theproximal end of tip member 43, or to core wire 342 adjacent thereto. Thebraided, or spirally wound tubular structure of torque member 384permits it to transmit rotation forces between shaft 144 and tip member43, and to do so at any length required to accommodate longitudinaldisplacement of shaft 144 and tip member 43 during transformation ofoccluder element 325 between a collapsed configuration and an expandedconfiguration.

In occluder guidewire 320, second proximal segment 392 is locatedproximally of first proximal segment 390 and has an enlarged diameterapproximating the outer diameter of shaft 144. Reinforcement coil 396surrounds first proximal segment 390 between second proximal segment 392and the proximal end of hollow shaft 144. Coil 396 has about the sameouter diameter as shaft 144, and helps prevent kinking of the portion offirst proximal segment 390 that extends from hollow shaft 144.Reinforcement coil 396 can vary in length to accommodate longitudinaldisplacement of shaft 144 and core wire 342 during transformation ofoccluder element 325 between a collapsed configuration and an expandedconfiguration.

Third proximal segment 394 is located proximally of second proximalsegment 392 and is adapted for engagement to a guidewire extension (notshown), as is well known to those of ordinary skill in the art ofguidewires. Examples of guidewire extensions usable with occluderguidewire 320 and other embodiments of the invention are shown in U.S.Pat. No. 4,827,941 (Taylor), U.S. Pat. No. 5,113,872 (Jahrmarkt et al.)and U.S. Pat. No. 5,133,364 (Palermo et al.).

FIG. 14 depicts a fifth embodiment of the invention in which occluderguidewire 420 incorporates several elements that are similar to thecomponents of occluder guidewire 320. For example, occluder guidewire420 has core wire 442 disposed within liner 145, which is disposedwithin hollow shaft 144. Transition sleeve 270 is slidably disposedabout a distal portion of hollow shaft 144 and extends distally therefrom. Proximal stop 481 protrudes radially outward from core wire 442,and distal stop 482 protrudes radially inward from the distal end oftransition sleeve 270. Proximal stop 481 has a maximum transversedimension, such as an outside diameter, that is greater than atransverse inner dimension, such as an inside diameter, of distal stop482. Proximal stop 481 is disposed proximal to and is capable ofinteracting with distal stop 482 to transmit distally directed axialforce from core wire 442 to transition sleeve 270.

As illustrated in FIG. 15A, proximal stop 481 may comprise a short coilfixed in the desired position around core wire 442. To increase thestrength of the attachment of proximal stop 481 to core wire 442, atleast a section of the coil may be longitudinally expanded. Theresulting gaps in the coil can be permeated by a suitable bondingmaterial, e.g., solder or adhesive, to both a larger diameter and agreater length, in comparison to unexpanded coils, as shown.

FIG. 15B illustrates a modified form of the stops shown on occluderguidewire 420 in FIG. 14. Proximal stop 481′ may be created with metalor plastic elements, such as solder or polyimide bands, as describedabove regarding occluder guidewire 320. Distal thrust bearing 483 is ofthe cylindrical, plain, anti-friction type and is disposed about corewire 442 between proximal stop 481′ and distal stop 482. Distal thrustbearing 483 serves, as a thrust washer, to reduce rotating frictionbetween stops 481′ and 482, especially while occluder 325 is beingforced into the collapsed configuration by the push-pull manipulationsdescribed above regarding occluder guidewire 320. Reduced rotatingfriction facilitates turning core wire 442 within collapsed occluder325, thus providing enhanced steering of occluder guidewire 420 throughtortuous curves and branches of a patient's vasculature. Distal thrustbearing 483 may comprise a ring of low-friction material such as afluoropolymer, a polyamide, HDPE or polyimide/fluoropolymer compositetubing as discussed above regarding liners 145, 145′ and 145″.Alternatively, distal thrust bearing 483 may comprise a solid ringhaving a slippery coating applied thereto. Distal thrust bearing 483 maybe freely situated in the described location, or it may be fixed to anyof the adjacent components such as core wire 442, proximal stop 481′ ordistal stop 482.

In occluder guidewire 420, occluder 325 is self-expanding and ispositioned generally concentrically with the distal portion of shaft144. Alternatively, filter 25 may be substituted for occluder 325 tocreate a filter guidewire in accordance with the fifth embodiment of theinvention. As described above with respect to occluder guidewire 320,occluder 325 may comprise a tubular braid that is coated with an elasticmaterial to render it non-porous.

As shown in FIG. 14, occluder distal end 327 is fixedly coupled totransition sleeve 270, and occluder proximal end 329 is rotatablycoupled to shaft 144 at a location proximally adjacent the distalportion thereof. Occluder proximal end 329 may form a rotatable ring byany suitable means such as heat treatment of the braid, the use offillers such as solder or adhesives, the addition of an internal orexternal ring element, or combinations of these methods. For example,FIG. 16 shows slip ring 487 located inside occluder proximal end 329.

In occluder guidewire 420, distal check element 486 protrudes radiallyoutward from shaft 144 distal of occluder proximal end 329. When hollowshaft 144 is drawn proximally over core wire 442, distal check element486 may contact occluder proximal end 329, to which it may transmitproximally directed force from shaft 144. Optionally, proximal checkelement 488 protrudes radially outward from shaft 144 proximal ofoccluder proximal end 329. When hollow shaft 144 is slid distally overcore wire 442, proximal check element 488 may contact occluder proximalend 329, to which it may transmit distally directed force from shaft144. Distal and proximal check elements 486, 488 may comprise rings,bands, coils, pins, adhesive dots, distortions in shaft 144, or anyother cooperating features that can effectively check longitudinalmovement of occluder proximal end 329 while permitting rotation thereof.Thus, proximal end 329 is rotatable about shaft 144, but may belongitudinally fixed between distal and proximal check elements 486, 488respectively. Occluder 325 is free to rotate about the supportingsteerable guidewire comprising, inter alia, shaft 144 and core wire 442,because transition sleeve 270, with occluder distal end 327 fixedthereto, is also rotatable about the steerable guidewire. Of course, theinverse description may be more clinically significant, i.e., thesteerable guidewire can be rotated freely within occluder 325, whetheroccluder 325 is in the deployed configuration or the collapsedconfiguration.

Occluder guidewire 420 includes tracking member 470 fixed alongside thedistal end of core wire 442. Tracking member 470 is a relatively shorttube that is open at both ends and is sized to fit slidably over anotherguidewire. Tracking member 470 permits occluder guidewire 420 to beguided into a patient's vasculature along with, or by sliding over,another guidewire. Occluder guidewire 420 can also be exchanged easilyover an indwelling guidewire. Because tracking member 470 envelopes onlya short section of the other guidewire, various types of treatmentcatheters can be introduced over the other guidewire while occluderguidewire 420 is positioned in the patient. The clinician is thuspresented with useful options of advancing therapeutic catheters overoccluder guidewire 420, or the other guidewire, or both guidewires.

During use of occluder guidewire 420, occluder 325 may be collapsed byadvancing core wire 442 distally through shaft 144 and transition sleeve270 until proximal stop 481 engages distal stop 482, as shown in FIG.14. Continued advancement of core wire 442 through shaft 144 will drawsleeve 270 along, but preferably not off of, the distal portion ofhollow shaft 144. The relative longitudinal movement of sleeve 270 withrespect to shaft 144 causes occluder distal end 327 to separate fromoccluder proximal end 329, thus transforming occluder 325 from anexpanded configuration to a collapsed configuration, as shown in FIG.14. Reversing the above manipulation, i.e., drawing core wire 442proximally through shaft 144, permits occluder 325 to expand itself.Self-expansion of occluder 325 will stop when one of several conditionsis met, similar to the description above with respect to self-expandingfilter 25 of filter guidewire 220. Thereafter, continued withdrawal ofcore wire 442 will draw its distal end proximally within transitionsleeve 270, creating axial separation (not shown) between stops 481,482, thereby allowing the distal end of transition sleeve 270, withdistal stop 482, to slide freely along the distal end of core wire 442between proximal stop 481 and tracking member 470. Thus, in the deployedconfiguration of occluder guidewire 420, occluder 325 can self-expand orself-adjust its apposition with the vessel wall.

FIG. 16 depicts a sixth embodiment of the invention in which occluderguidewire 520 incorporates several elements that are similar to thecomponents of occluder guidewires 320 and 420. Elements, and theirpositions, that are common to occluder guidewires 320 and 520 are shaft144, liner 145, transition sleeve 270, occluder 325, core wire 342, tipmember 43, stops 381, 382, and check elements 486, 488. Occluderguidewire 520 has slip ring 487 fixed within occluder proximal end 329.Slip ring 487 is rotatably mounted about hollow shaft 144 between distaland proximal check elements 486, 488 respectively. The arrangement shownprovides unlimited rotation of shaft 144 and core wire 342 withinoccluder 325, as described above with respect to occluder guidewire 420Proximal thrust bearing 489 is of the cylindrical, plain, anti-frictiontype and is disposed about shaft 144 between slip ring 487 and distalcheck element 486. Proximal thrust bearing 489 serves to reduce frictionbetween slip ring 487 or occluder proximal end 329 and distal checkelement 486, thus facilitating rotation of shaft 144 within occluder325, especially when occluder 325 is being forced into the collapsedconfiguration by the push-pull manipulations described above regardingoccluder guidewire 320. Proximal thrust bearing 489 may comprise a ringof low-friction material such as a fluoropolymer, a polyamide, HDPE orpolyimide/fluoropolymer composite tubing as discussed above regardingliners 145, 145′ and 145″. Alternatively, proximal thrust bearing 489may comprise a solid ring having a slippery coating applied thereto.Proximal thrust bearing 489 may be freely situated in the describedlocation, or it may be fixed to any of the adjacent components such asshaft 144, occluder proximal end 329, distal check element 486 or slipring 487. It may be especially advantageous to construct an inventiveapparatus having a combination (not shown) of distal thrust bearing 483of occluder guidewire 420 and proximal thrust bearing of occluderguidewire 520.

As shown in FIG. 16, occluder guidewire 520 has tracking member 470fixed alongside the distal end of the apparatus at the distal end oftransition sleeve 270. Since occluder guidewire 520 has both a steerabletip member 43 and tracking member 470, a clinician can choose to insertand steer the device independently through a patient's vasculature, orthe clinician can advance the same device over another guidewire. Incontrast to occluder guidewire 420, rotation of core wire 342 and tipmember 43 does not attempt to revolve core wire 342 around anotherguidewire, if one is present within tracking member 470. Both occluderguidewires 420 and 520 can be inserted to a desired location overanother guidewire, which can then be removed, if so desired. A treatmentcatheter can be advanced over occluder guidewires 420 and 520 whetherthe other guidewire has been removed or not.

To adjust and maintain the relative longitudinal and/or rotationalpositions of core wires and the surrounding hollow shafts in the variousembodiments of the invention, a removable handle device (not shown) of atype familiar to those of skill in the art may be used. Such handledevices can have telescoping shafts with collet-type clamps that griprespectively the core wires and shafts in the various embodiments ofguidewire apparatuses according to the present invention. The handledevice can also serve as a steering handle, or “torquer” which is usefulfor rotating small-diameter steerable-type guidewires that may beincorporated in the instant invention.

A method of using of a guidewire apparatus of the invention is describedas follows. It should be noted that the example described below isunnecessarily limited to a filter guidewire embodiment. Filter guidewire20, having self-expanding filter 25 and hollow shaft 44 is provided, andadvancing core wire 62 through shaft 44 collapses filter 25. With filter25 in the collapsed configuration, filter guidewire 20 is advanced intothe patient's vasculature until filter 25 is beyond intended treatmentsite 15. Withdrawal of core wire 62 allows filter 25 to expand. Withfilter 25 deployed into contact with the vessel wall, a therapeuticcatheter is advanced over filter guidewire 20 to treatment site 15, andtherapy, such as balloon angioplasty, is performed. Any embolic debrisgenerated during the therapy is captured in filter 25. After the therapyis completed, the therapeutic catheter is prepared for withdrawal, as bydeflating the balloon, if so equipped. Advancing core wire 62 throughshaft 44 collapses filter 25. Finally, filter guidewire 20 and thetherapeutic catheter can be withdrawn separately or together, along withcollected embolic debris contained within filter 25. If an occluderguidewire of the invention were substituted for a filter guidewire inthe above-described method, then aspiration of trapped embolic materialwould be performed with a separate catheter before collapsing theoccluder element.

One benefit of the structures of filter guidewires 20, 120 and 220 isthat guidewire tip member 43 forms a fixed length tip of the device,regardless of the configuration of filter 25. Conversely, in occluderguidewire 320, the tip length changes as occluder distal end 327 slidesalong tip member 43 during transformation of occluder 325 betweenexpanded and collapsed configurations. The variable tip length ofoccluder guidewire 320 provides a short tip when occluder 325 iscollapsed, but the tip needs to lengthen distally of treatment site 15,if possible, during expansion of occluder 325. During deployment offilter guidewires 20, 120 and 220, the distal tip position of the devicecan remain fixed relative to treatment site 15. This is accomplished bythe user holding core wires 42, 142 or 242 anchored relative to thepatient, while applying tension to shafts 44 or 144 in the proximaldirection. Filter 25 can be maintained in a collapsed configuration by afriction mechanism including bends 160, or by applying proximal tensionto shafts 44, 144, thus holding filter proximal end 29 apart from filterdistal end 27. Releasing the tension on shafts 44, 144, or advancingthem manually, allows filter 25 to expand by filter proximal end 29translating distally towards filter distal end 27. During this filterdeployment, however, the distal tip does not need to move relative tofilter 25 or treatment area 15.

While the invention has been particularly shown and described withreference to the preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and detail may bemade there in without departing from the spirit and scope of theinvention. For example, the invention may be used in any intravasculartreatment utilizing a guidewire and wherein the possibility of looseningemboli exists. Although the description herein illustrates angioplastyand stent placement procedures as significant applications, it should beunderstood that the present invention is in no way limited to thoseenvironments.

We claim:
 1. A guidewire apparatus comprising: an elongate hollow shaft;a core wire movably disposed within the hollow shaft and having a distalend extending there from; a transition sleeve slidably disposed about adistal portion of the hollow shaft and the core wire distal end; and atubular protection element having a distal end fixed about thetransition sleeve and a proximal end rotatably coupled about the hollowshaft at a location proximal to the distal portion of the hollow shaft,the protection element having a collapsed configuration with a firstlength and an expanded configuration with a second length shorter thanthe first length.
 2. The guidewire apparatus of claim 1, furthercomprising a liner interfitted between the core wire and the hollowshaft, the liner having inner and outer surfaces, wherein at least oneof the surfaces has a low coefficient of friction.
 3. The guidewireapparatus of claim 1, further comprising a tracking member being adaptedto slide over another guidewire and being fixed alongside a distal endof the guidewire apparatus.
 4. The guidewire apparatus of claim 3,wherein the tracking member is fixed alongside the core wire distal end.5. The guidewire apparatus of claim 3, further having a flexible tipmember fixed about the core wire distal end, wherein the tracking memberis fixed alongside a distal end of the transition sleeve.
 6. Theguidewire apparatus of claim 1, further comprising: a distal stopelement fixed within a distal end of the transition sleeve; and aproximal stop element fixed about the core wire distal end at a locationproximal to the distal stop element; wherein the proximal stop elementhas a maximum transverse dimension greater than a transverse innerdimension of the distal stop element.
 7. The guidewire apparatus ofclaim 6, further comprising a distal thrust bearing fitted about thecore wire distal end and disposed longitudinally between the distal stopelement and the proximal stop element.
 8. The guidewire apparatus ofclaim 6, further comprising a flexible tip member fixed about the corewire distal end and being disposed radially between the core wire distalend and the proximal stop element.
 9. The guidewire apparatus of claim6, wherein the proximal and distal stop elements cooperate to limitsliding of the transition sleeve in a proximal direction along the corewire.
 10. The guidewire apparatus of claim 1, further comprising adistal check element fixed about the hollow shaft at a location distalto the protection element proximal end.
 11. The guidewire apparatus ofclaim 10, further comprising a proximal thrust bearing fitted about thehollow shaft and disposed longitudinally between the distal checkelement and the protection element proximal end.
 12. The guidewireapparatus of claim 10, wherein the distal check element limits slidingof the protection element proximal end in a distal direction along thehollow shaft.
 13. The guidewire apparatus of claim 1, further comprisinga proximal check element fixed about the hollow shaft at a locationproximal to the protection element proximal end.
 14. The guidewireapparatus of claim 13, wherein the proximal check element limits slidingof the protection element proximal end in a proximal direction along thehollow shaft.
 15. The guidewire apparatus of claim 1, wherein theprotection element is a filter.
 16. The guidewire apparatus of claim 1,wherein the protection element is an occluder.
 17. The guidewireapparatus of claim 1, wherein the protection element isself-transformable between the collapsed configuration and the expandedconfiguration.